Voice-activated pulser

ABSTRACT

A voice-activated pulser can trigger an oscilloscope or a meter, upon a simple voice command, thereby enabling hands-free signal measurements. The pulser can also be used to control the circuit under test, activating it or changing parameters, all under voice control. The pulser includes numerous switch-selectable output modes that allow users to generate complex, tightly-controlled diagnostic sequences, all activated upon a voice command and hands-free. The invention includes a fast, robust command-interpretation protocol that completely eliminates the expense and complexity of word recognition. Visual indicators display the device status and various operating modes, and also confirm each output pulse. The device receives voice commands directly through an internal microphone, or through a detachable headset, and confirms each command with an acoustical signal in the headset.

BACKGROUND OF THE INVENTION

The invention relates to voice-activated devices, and particularly todevices for generating electronic signals responsive to voice commands.

A variety of new voice-activated products have appeared recently,ranging from the sublime (in-car GPS, phone dialers, computer dictation)to the ridiculous (voice-activated t-shirts, coffee pots, light-sabers).The most practical near-term application for voice-activation technologyis for hands-free triggering of electronic instruments such asoscilloscopes and meters. Oddly, this has received almost no attention.

Everyone with experience in electronic testing knows how hard it is totrigger a scope while holding multiple probes against specific locationson the circuit under test. Fine-pitch parts don't make this any easier.Sometimes it is sufficient to free-run the scope or use some othersignal as a trigger, but in many cases the engineer needs to trigger themeasurement directly, at a particular time. for other measurements, itis necessary to activate or modulate the circuit under test, for exampleto compare waveforms under two different conditions. Most engineers haveonly two hands and therefore cannot trigger the scope manually oractivate the circuit under test, while holding multiple probes inposition (although some have been known to trigger the scope with atoe.)

A single patent (U.S. Pat. No. 7,027,991) partially mitigates thisproblem with an oscilloscope that can be controlled by voice commands.This is a step in the right direction, but it fails to exploit theversatility of voice-activation technology in several aspects. First,the prior-art scope trigger is usable only for the instrument thatcontains it, whereas a truly versatile stand-alone device should be ableto trigger a wide range of voltage-measurement instruments simply byconnecting with a cable. Second, the prior-art systems are not able toactivate the circuit under test, because there is no provision for avoice-responsive output signal. Third, the prior-art systems provide noexternal indication as to when the system is available or inhibited (ie,deadtime, busy, etc.). Fourth, the prior-art systems have no way toalternate a state condition on the circuit under test, which is anextremely useful technique for diagnosing operational problems.

Given the advantages of voice-activation of instruments, why is it notwidely available? The answer is that all voice-activated measurementsystems employ full word recognition algorithms, resulting in extremelyhigh cost and complexity, complex software, often a cumbersome“training” period, and lack of speaker universality. And still they havean annoying delay between the command and the pulse. To take oneexample: a commercial dictation routine, although costly, works prettywell—on a $2500 machine with a fast multi-core processor and gobs ofcache, and after 60 minutes of tedious training. Seriously, if you onlywant to trigger a scope, word-recognition is overkill.

What is needed is a low-cost, easy to use, extremely versatile device togenerate an output signal, capable of triggering an oscilloscope as wellas a circuit under test, all upon one or two simple voice commands.Preferably the device includes multiple operational modes and multipleoutputs so that the user can select the mode and output for each type ofmeasurement. Even more preferably, the device would involve no training,no software installation, no special adaptors, no anything else; justconnect the device to the scope and trigger it. Such a device willsimplify innumerable measurement tasks, thereby earning the heartfeltappreciation of electronic test engineers everywhere.

BRIEF SUMMARY OF THE INVENTION

The invention is a device and a method to generate an output signal,responsive to a simple voice command, to activate a triggerableelectronic system such as an oscilloscope or a circuit under test. Thedevice can cause the circuit under test to produce a responsivediagnostic voltage, which is then measured by a measurement instrument,thereby allowing a user to diagnose a problem with the test circuit. Or,the device can cause a triggerable measurement instrument, such as ameter or oscilloscope, to perform the measurement when so activated. Inboth configurations, the invention simplifies the task by allowing theuser to control the timing and character of the measurements, easily andhands-free.

The invention involves several different signals and voltages, which canget confusing. For clarity, each type of signal or voltage will beidentified specifically by name. An “output signal” is an electronictransmission, such as a pulse, emitted by the inventive device upon avoice command. The invention may generate multiple distinct outputsignals upon different commands, the output signals being termed a“type-1 output signal”, a “type-2 output signal”, and so forth. Theinvention may also generate a “readiness signal” indicating whether theinvention is inhibited or is ready to receive voice commands. A“microphone signal” is a low-level electronic signal coming directlyfrom a microphone, and an “amplified signal” is the raw signal afteramplification and optional filtering. A “threshold voltage” is a voltageagainst which the amplified signals are compared to detect the sound ofa spoken command. A “diagnostic voltage” is a voltage or series ofvoltages generated by the circuit under test, and which the measurementinstrument measures.

The voice command comprises any utterance produced by the user withintent to activate the triggerable system. In the simplest version, theinvention responds to every command by generating the same outputsignal; the user simply says “Go” and gets one pulse. Or, for greaterversatility, the inventive device may generate a variety of differentoutput signals responsive to different commands. Preferably the deviceuses a robust and universal command recognition protocol readilyimplemented in a low-cost microcontroller, such as syllable-counting. Inthe syllable-counting protocol, the invention counts the number ofcommand syllables by detecting a brief interval of relative silencebetween the syllable sounds. It then generates a type-1 output signalfor a single-syllable command, a type-2 output signal for adouble-syllable command, and so forth. The invention produces a type-1output signal when the user says a single-syllable command such as “Go”,and a type-2 output signal when the user says a double-syllable commandsuch as “Reset”. The invention may additionally respond tothree-syllable commands with a type-3 output. The syllable-countingprotocol is easy and intuitive for users, yet is versatile enough for anunlimited range of measurements.

The inventive output signals are any electronic transmissions from theinventive device. Usually the output signals comprise either a briefvoltage pulse or an alternating voltage level that alternates upon eachvoice command. The output signals may comprise a voltage that increasesstepwise upon each separate syllable of the command, rising to 1 voltupon the first syllable, then 2 volts upon the second syllable, then 3volts if there it a third syllable, and then returning to zero volts atthe end of the command-processing routine. As a further alternative, theoutput signals may be digital communication messages such as USBsignals, that activate a computer-based measurement instrument such as aPC-oscilloscope and the like. The various distinct output signals(type-1, type-2, etc) are usually provided on separate conductors.Alternatively, the output signals may share a single conductor if thevarious output signals are distinct. For example a type-1 signal may bea positive pulse, and a type-2 signal may be a negative pulse, bothappearing on the same conductor at different times. Or, the outputsignals may comprise frequency modulation, pulse width modulation,analog voltage patterns, complex digital messages, different currents,and different impedances, presented on separate or shared conductors.

The inventive device is detachably connected to the triggerableelectronic system, using connectors and a cable or wire or otherconductor, so that the output signal can activate it. The triggerablesystem comprises any electronics responding to the output signal,including a measurement instrument or a circuit under test. Ameasurement instrument is any means for measuring a diagnostic voltage,or a series of voltages, on the circuit under test. Such instrumentsinclude oscilloscopes and logic analyzers and spectrum analyzers andmultichannel analyzers and computer-based measurement systems, and anyother instruments that measure a series of voltages over time. Themeasurement instrument may also be a sample-and-hold meter that measuresa single voltage when so triggered. Such a meter may measure a voltageper se, or it may measure a voltage value that is related to some otherquantity such as a current or a temperature or an electromagnetic fieldor a light intensity for example. Importantly, the invention is notrestricted to a particular measurement instrument, but allows the userto trigger virtually any instrument simply by connecting the inventionto it and issuing a voice command.

The triggerable system may also be the circuit under test, when theoutput signal is connected to the circuit under test so as to control oractivate it. The circuit under test is any electronic circuit beingmeasured by the user, including circuit boards, discrete devices,complete systems, and networks as well as communication lines betweenthem, so long as the output signal triggers or otherwise activates thecircuit. Normally the circuit under test responsively generates adiagnostic voltage or a series of diagnostic voltages, which ameasurement instrument subsequently measures for the purpose ofrevealing something about the circuit under test. The measurementinstrument may be free-running, or triggered by a change in thediagnostic voltage, or triggered by the same output signal or adifferent output signal from the inventive device. The output signal canenable or disable a function of the circuit under test, or alternate acircuit condition, or prompt the test circuit to generate a pulse or adigital communication message, as well as many other operations thatwill occur to test engineers when they use this invention. Importantly,the invention is not restricted to a particular test circuit, but allowsthe user to activate virtually any circuit simply by connecting theinvention to it and issuing a voice command.

The invention includes means for detecting voice commands anddiscriminating them from background noise, typically including amicrophone, amplifiers, filters, and a processor. The microphoneconverts sound to an electronic raw signal, from which the amplifiersand filters then produce an amplified signal, which the processorcompares to a predetermined threshold value. The invention may includerectifying and smoothing to further separate command sounds frombackground noise. The invention determines that a sound is detected whenthe amplified signal (with or without rectification) exceeds thethreshold, and no sound is detected when the amplified signal remainsbelow the threshold. Preferably the invention selects a frequency bandcorresponding to the human voice, and suppresses sounds outside thatfrequency band.

The invention may include manual or automatic adjustment means foradjusting the acoustical sensitivity to mitigate a varying level ofbackground noise. For example, the invention may derive an average noisevalue by monitoring the amplified signals, and then increase or decreasea threshold value accordingly. Preferably the invention suppresses thisprocess while a command sound is detected, to avoid unduly biasing theadjustment. Or, the invention may include manual adjustment means forvarying the sensitivity. The manual control may be a potentiometer thatattenuates the microphone signal, or varies the gain of the amplifier,or varies a DC level that a digital processor then uses as a thresholdlevel. Other means for varying the sensitivity will be apparent to many.

The invention may discriminate single-syllable commands frommulti-syllable commands. To do so, the invention may emphasize thevoiced command sounds such as vowels, while suppressing unvoicedconsonant sounds. For example the “s” in “Reset” has higher frequenciesand lower sound amplitude than the vowel sounds. The invention exploitsthis by filtering out the high frequency sounds and amplifying thevoiced vowel sounds. “Reset” is thus recognized as having two voicedperiods separated by a brief gap of substantially less voiced sound,comprising a double-sound or double-syllable command. In contrast, “Go”has only one uninterrupted period of voiced sound, and thus would beinterpreted as a single-sound command. The invention may detect commandswith three syllables in a similar way.

The invention may impose deadtime periods, of duration Td for example,during which all sounds are ignored. The deadtime may be simply a fixedwaiting period. Or, much more preferably, the deadtime is retriggerablein that if any sound is detected during Td, then the Td period isstarted over, and it continues to do so until a full Td period expireswith no further sound detected therein. The deadtime may be imposedbefore accepting any command sound, thereby assuring that prior commandshave finished; or the deadtime may be imposed at the end of a command,thereby assuring that the current command is finished before acceptingany further commands. Such pre- and post-deadtimes are operationallyequivalent after the first instance.

The invention may analyze commands by marking a series of time periods.After a deadtime period, the invention then waits until a command soundis detected. It then determines when the first syllable is finished bywaiting until there is no additional sound during a short interval Ta.Ta is chosen to be shorter than the non-voiced interval betweensyllables, in most two-syllable words. Then, after the first syllable isfinished, the protocol waits for a longer period Tg, during which itlistens for a second syllable in the command. Tg is chosen to be longenough to catch the second syllable of most command words. If no soundoccurs during Tg, then the command is a single-sound command. If asecond sound occurs during Tg, then it is a double-sound command. Todetect a three-sound command, the Ta-Tg sequence is repeated. Tosummarize, the syllable-counting sequence is: (wait for deadtimeTd)-(wait for first sound)-(wait for end of first syllable)-(listen forsecond sound during Tg)-(generate output signal).

In practice, people easily use one- and two-sound commands, orthree-sound commands with care. Commands with four or more syllableswill work, but they tend to become unwieldy. Td should be chosen longenough to ensure that prior commands have finished, but not so long thatthe system becomes balky. Typically Td is 100 to 500 msec(milliseconds). Ta must be shorter than the unvoiced interval betweensyllable sounds, but long enough to ensure that the first syllable isfinished. Typically Ta is 20 to 200 msec. Tg is long enough to catch thesecond syllable sound, but not so long that the next command ismistakenly counted as a double-sound command. Typically Tg is 100 to1000 msec.

The invention may also measure the duration of each syllable sound bystarting a timer when the first sound begins, then stopping the timerafter the Ta period, and optionally subtracting Ta to get the actualsound duration time. Typically the duration of a syllable is about 50 to500 msec. The invention may exclude background noises that have aduration outside than this range.

Often it is desirable to lock the device temporarily, for example toavoid triggering on noise or to freeze a display. Therefore theinvention may include a holding mode, and means for turning the holdingmode on and off. In the holding mode, the invention ignores all voicecommands and inhibits all outputs, thereby locking a previously-obtaineddisplay or measurement.

The invention may include a readiness indicator that depends on whetherthe invention is ready to receive a voice command. The invention is notready to receive a voice command when it is inhibited due to a deadtimeor holding mode for example. The readiness indicator shows the user whento issue voice commands. The invention may also generate a readinessoutput signal, which could be used to gate the circuit under test or totrigger an oscilloscope for example.

The invention may include a battery for power, and may include anindicator to alert the user when the battery voltage is getting low. Or,the invention may include an internal or external power supply. Or, whenthe invention is connected to a computer-based measurement system by adigital communication cable such as a USB cable, the invention may drawpower from it.

The invention may include an internal microphone or a detachableexternal microphone using an audio plug, for example. The externalmicrophone may include a wireless link including a radio or opticaltransmission. Whenever the external microphone is plugged in, theinternal microphone may be automatically disconnected to avoidinterference. The external microphone may be a bench-type microphone, ora computer-based microphone, or a wearable microphone. Wearablemicrophones tend to have better signal properties than internalmicrophones, since a wearable microphone is generally closer to the userand tends to be less susceptible to background noises. A wearablemicrophone may also include a speaker, as in a headset. The inventionmay generate an acoustical command-validation signal, such as a tone, inthe wearable speaker when each output signal is generated. Preferablythe invention generates a different tone for a single- anddouble-syllable command. Such a tone informs the user when each voicecommand is accepted, and also informs the operator immediately if acommand has been misinterpreted, or if the device triggers on backgroundnoise.

The invention may include visual indicators, such as LED's, showingvarious operational states of the device. The indicators may flashwhenever an output signal is generated, preferably with distinctindicators for type-1 and type-2 output signals. The invention maycommunicate its operational state to a computer for display or storage.

Structurally, the inventive device comprises a microphone, a circuitboard, an enclosure, and one or more output connectors carrying theoutput signals. The circuit board includes amplifiers (includingoptional filters and rectifiers) to amplify the raw signals from themicrophone, and processing means to detect command sounds by comparingthe amplified signals to a predetermined voltage threshold. Theprocessing means also measures time intervals such as deadtimeintervals, and generates the output signals. The enclosure encloses thecircuit board and supports the output connectors. The output connectorsmay be coaxial such as BNC and SMA jacks, or single-conductor connectorssuch as banana jacks or screw terminals, or digital communicationconnectors such as USB jacks for example. Typically the enclosureincludes a battery, an on-off switch admitting power from the battery tothe circuit board, an indicator indicating when the system is ready toreceive voice commands, an indicator indicating when the output signalis generated, a jack for connecting an external microphone, and asensitivity control.

The invention is also a method, to activate a triggerable electronicsystem comprising a measurement instrument or a circuit under test,responsive to a spoken command. The inventive method discriminatescommands from ambient noise on the basis of amplitude and frequency andtiming. The method includes the steps of connecting the invention to themeasurement instrument or to the circuit under test; then detecting thecommand sounds by amplifying the raw signals from a microphone, a soundbeing detected when the amplified signals exceed a threshold value; andthen generating an electronic output signal which then activates thetriggerable electronic system. The output signal either causes themeasurement instrument to measure a diagnostic voltage on the circuitunder test, or the output signal causes the circuit under test toproduce a diagnostic voltage, which the measurement instrumentsubsequently measures. Or, the circuit under test and the measurementinstrument may both be triggered by the same output signal or bydifferent output signals at different times.

Frequency discrimination may be achieved with analog filters or bydigital analysis of the sound signal, preferably accepting sounds withfrequencies in a bandwidth corresponding to the voiced syllables, whilerejecting frequencies above or below that band. Amplitude discriminationmay be achieved by comparing the amplified signal to a single thresholdvalue; or, since sound waves have both positive and negativefluctuations, comparing the amplified signal to two threshold valuescorresponding to positive and negative variations relative to a mean. Asa further alternative, the sound may be rectified and optionallysmoothed, and then the rectified signal may be compared to a threshold.The step of amplifying includes optional filtering, rectifying, andsmoothing. The step of comparing includes comparing both positive andnegative variations with their respective threshold values.

The inventive method may include waiting for a deadtime period Td ofrelative silence, to ensure that any prior commands have completed, andto avoid multiple-triggering. The Td period may be imposed beforeaccepting any commands, or after each detected sound.

The inventive method may include counting the number of separate voicedsounds in the spoken command, and generating different output signalsresponsive to commands with different numbers of voiced sounds. Themethod then includes a step of detecting the end of the first voicedsound by waiting until an interval Ta expires with no further sounddetected therein. Thus the first Ta period of silence, following acommand sound, indicates that the first syllable is finished. Then,after the Ta period, the invention waits an additional Tg period to seeif a second syllable arrives. The invention generates a type-1 signalfor a single-sound command if no further sound is detected during Tg,and generates a type-2 signal for a double-sound command if any sound isdetected during Tg. The method may also include waiting additional Ta-Tgperiods, to identify commands with three or more voiced syllables, andgenerating the appropriate output signal for each.

The method may include measuring the duration of each detected syllablesound, and rejecting the command if the duration is outside apredetermined range. Likewise the command may be rejected if any portionof the sound exceeds a maximum expected level, or if the two syllablesof a type-2 command are have very different sound levels or verydifferent frequency ranges. These steps allow the invention to avoidresponding to certain background noises.

The step of generating the output signal may comprise generating a briefoutput pulse upon a voice command, or generating an output voltage thatalternates between two voltage values upon each command, or generating avoltage that increases, stepwise, upon each successive syllable untilthe command is finished. Or the output signal may involve otherelectronic transmissions including amplitude and frequency modulation,and digital communication messages such as USB messages.

The method may include setting a readiness parameter according towhether voice commands are inhibited or enabled. For example, thereadiness parameter is turned on after the Td deadtime is expired, andthe readiness parameter is turned off when a holding mode has been set.The method may include generating a readiness output signal comprising afirst voltage level when voice commands can be received, and a secondvoltage level when voice commands are inhibited. The method may alsoinclude activating an indicator based on the readiness parameter,thereby showing the user when a voice command can be accepted.

The method includes a protocol to determine the timing of the outputsignals. In one protocol, termed the immediate-output protocol, eachoutput signal is generated immediately upon detecting each syllablesound of the command. This provides the best responsiveness, butunavoidably generates multiple output signals upon multi-syllablecommands. That is because there is no way to know, at the start of acommand, whether it will have one or two or three syllables. In theimmediate-output mode, a type-1 signal is generated immediately upon thefirst syllable of every command. If there is a second syllable, then itgenerates a type-2 signal immediately upon the second syllable sound,followed by a type-3 signal for a three-syllable command. This rapidmulti-pulse output sequence is useful in some measurement situations,for example to initiate a rapid sequence and then to measure a response.

In some situations, however, the user wants only a single output signalthat correctly matches the command type. Therefore the method mayinclude a delayed-output protocol in which the output signal isgenerated only after the command is finished. The delayed-outputprotocol ensures that the number of voiced periods in the command willbe determined first, and then the correct output signal is generated.The delayed-output protocol includes performing the Ta-Tg waitingintervals first, and then generating the appropriate output signal onlyafter Tg expires. Thus in the delayed-output protocol, only one outputsignal is generated, and it corresponds correctly to the command.However, the delayed-output protocol necessarily involves a perceptibletrigger hesitation while the period Tg expires.

The inventive method may include a third protocol, termed theregulated-output protocol, which provides a prompt response (as in theimmediate mode) but eliminates multiple pulsing (like the delayed mode).The regulated-output protocol includes a regulator parameter that can beset to enable and disable the type-1 outputs. The regulator parameter isset to the enabling state after each double-syllable command, andbecomes disabling after each single-syllable command. When the parameteris enabling, the invention generates a type-1 signal as soon as anycommand is detected, and then the parameter is disabled to prevent anyfurther type-1 output signals. Then, upon the next double-syllablecommand, the parameter is re-enabled. Thus, a double-syllable commandresets the regulator parameter, and then a single-syllable commandgenerates an immediate type-1 output signal. The net effect is togenerate only one output signal, according to the command type, butwithout a processing delay.

The user employs the regulated-output protocol by alternately speakingsingle- and double-syllable commands, such as “Go . . . Reset . . . Go .. . Reset”. The regulator parameter is enabled upon each double-syllablecommand, and is disabled upon each single-syllable command. The userobtains one output signal at a time, of the correct type, immediatelyupon the first sound of the syllable corresponding to the command type.If the user issues a series of single-syllable commands in a row, suchas “Go . . . Go . . . Go”, then only the first command generates anoutput signal, and the subsequent commands are ignored because at thattime the regulator parameter has not yet been re-enabled.

The regulated-output protocol has another useful feature in which theuser may obtain multiple output pulses when needed. To do so, the userspeaks sequential two-syllable commands such as “Reset . . . Reset . . .Reset”. Since each of these commands has two syllables, it re-enablesthe regulator parameter each time. Therefore, a type-1 output isgenerated upon the first syllable of the next “Reset” command, followedrapidly by a type-2 output upon the second syllable. The advantage ofthe regulated-output protocol, is that the user can obtain single pulsesor multi-pulses at will, and control both the timing and the pulse typesfor any particular measurement task, simply by speaking single- ordouble-syllable commands.

Among the many advantages of the syllable-counting protocol are low costand ease of use. Command interpretation is independent of the languageor accent or gender or intonation of the speaker. It does not matterwhat words the speaker uses, so long as the words have either one voicedsound period, or two voiced sound periods separated by a brief gap.While word recognition requires a full-performance computer with complexsoftware, the inventive protocol can be implemented with a tinymicrocontroller costing, literally, pennies (MC9RS08 KB2CSC, 48¢ in100's from Digikey).

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an embodiment, partially cut-away, of the inventive deviceconfigured to generate a single pulse output.

FIG. 2 shows the device in a test set-up to trigger an oscilloscope.

FIG. 3 shows an embodiment for generating multiple outputs with multipleoperating modes.

FIG. 4 shows a multiple-output device in a test set-up to activate acircuit under test and also trigger an oscilloscope.

FIG. 5 is a chart showing the sound and pulse waveforms forsingle-syllable commands and single-pulse outputs.

FIG. 6 is a flowchart showing the inventive method for single-syllablecommands and various output modes.

FIG. 7 shows the sound and pulse waveforms for a variety of commands.

FIG. 8 is a flowchart showing the inventive method for multi-syllablecommands.

DETAILED DESCRIPTION OF INVENTION

Referring to FIG. 1, an embodiment of the invention comprises a case 101enclosing a circuit board 102 and a battery 103. The case 101 is shownpartially cut-away as indicated by a dotted line. The circuit board 102includes a built-in microphone 104, an amplifier 105, and a processor106. The case 101 includes an output connector 107, an on-off switch108, an indicator 109, and a sensitivity adjustment 110.

The microphone 104 is a small electret transducer that converts soundwaves of a command into raw electrical signals. (Sound waves readilypass readily through the case 101.) The raw signals are amplified andfiltered by the amplifier 105 and then passed to the processor 106. Theprocessor 106 compares the amplified signals to a threshold voltage andgenerates the output signal when the amplified signals exceed thethreshold. The processor 106 also measures time intervals such asdeadtime intervals. The output signal then passes through the outputconnector 107 which is a BNC jack.

The amplifier 105 may comprise discrete components such as transistors,integrated circuits such as op-amps, or a sound detection package suchas the MC2830, so long as the gain is sufficient to allow commandrecognition. The amplifier 105 includes bandpass filters comprisingcapacitors to exclude signals outside a vocal frequency band of 100 Hzto 700 Hz. Optionally the amplifier 105 includes a rectifier to rectifythe amplified signals, and a filter to smooth the rectified signals.

The processor 106 may comprise a voltage comparator such as a LM339 tocompare the amplified signals to a threshold voltage, and a pulsegenerator such as one side of a 74123 monostable oscillator to form anoutput signal pulse. The other side of the '123 could be configured todemark a deadtime following each output pulse (the retriggerable featureis particularly useful in updating the deadtime interval). The outputsignal may be a short pulse or a voltage that alternates between twovoltage levels (such as +5V and ground) upon each voice command. If theoutput signal is selected to be an alternating voltage level, then theprocessor 106 includes a flip-flop such as the 74109 connected to theoutput of the voltage comparator to produce an alternating high-lowoutput upon each successive voice command. (CMOS may be used instead ofTTL if desired.) The processor 106 may include means for converting theoutput signal to a lower impedance such as a 50Ω line driver, or anemitter follower, or a transformer.

Alternatively, and more tidily, the processor 106 may comprise amicrocontroller such as the PIC12F675. The amplified signals can betested using the voltage comparator of the microcontroller, or digitizedby the built-in ADC and then compared to a numerical threshold value. Ineither case, the microcontroller then generates the output signal,comprising a pulse or an alternating output voltage or digital messageas desired. The processor 106 then illuminates the indicator 109, andalso demarks any deadtime periods. When the output signal is a digitalcommunication message, the processor 106 preferably includes a built-incommunication port such as a UART, USB, I²C, SPI, etc.

The on-off switch 108 is a SPST toggle switch that admits power from thebattery 103 to the circuit board 102. The sensitivity adjustment 110 isa potentiometer configured to vary the gain of the amplifier 105. Theindicator 109 is an LED connected to the processor 106 to indicate anoperational state of the invention. When the device is ready to receivevoice commands, the indicator 109 is illuminated green. When the outputsignal is then generated, the indicator 109 emits a yellow flash. Whenthe system is in a holding mode or otherwise is inhibited from receivingvoice commands, the indicator 109 is illuminated red. When the battery103 is getting low, the indicator 109 flashes red.

Referring to FIG. 2, the invention 201 may be employed to trigger anoscilloscope 202 which uses two probes 204 and 205 to measure voltageson certain locations of the circuit under test 203. A cable 206 connectsthe invention 201 to the oscilloscope 202.

The user first arranges the probes 204 and 205 to measure diagnosticvoltages at particular locations on the circuit under test 203.Obviously the user cannot activate the oscilloscope 202 while holdingthe probes 204 and 205 in place. Therefore the user issues a voicecommand such as “Go”, which causes the invention 201 to generate anoutput pulse, which travels along the cable 206 and triggers theoscilloscope 202. The oscilloscope 202 then performs a series of voltagemeasurements using the probes 204 and 205. The hands-free triggeringenables the user to quickly and easily take the data, thereby figuringout what's wrong with the circuit under test 203.

FIG. 3 shows an alternative embodiment having multiple outputs andvarious modes. The case 300 includes a type-1 output connector 301 whichcarries type-1 output signals responsive to single-syllable commands,and a type-2 output connector 302 which carries type-2 output signalsresponsive to double-syllable commands. The embodiment also has areadiness output connector 303 which is a SMA jack carrying a readinessoutput signal. The embodiment also has an alternating-output connector304 which is another SMA jack carrying an output signal that alternatesbetween two voltage levels upon each voice command.

The audio jack 305 is a 2.5 mm or 3.5 mm, 2-conductor or 3-conductorjack into which an external microphone (not shown) may be connected. Theaudio jack 305 also provides power to the external microphone. An on-offswitch 306 turns the system power son and off. A mode switch 307 is a3-position toggle switch to select the output timing mode asimmediate-output, delayed-output, or regulated-output. A sensitivitycontrol 308 is a potentiometer wired to generate a variable DC levelwhich is then used as a threshold level.

A set of indicators 309 are LED's that illuminate when the type-1 ortype-2 output signals are generated, or when the system is ready toreceive a command, or when the alternating-output signal is high or low.The embodiment also has a set of force-trigger buttons 310, which aretactile-type pushbutton switches that force the processor to generatetype-1 or type-2 output signals when pressed, even during a holding modeor when otherwise inhibited. Such a capability is useful for debugging asetup.

A hold-run switch 311 is a pushbutton switch that alternately turns theholding mode on and off when pressed. Voice commands are inhibited inholding mode.

FIG. 4 shows a test set-up using a multi-output embodiment of theinvention 401. The invention 401 activates both an oscilloscope 402 anda circuit under test 403, while the oscilloscope 402 measures diagnosticvoltages from the circuit under test 403 using the probes 404 and 405. Acable 406 connects the invention 401 to the oscilloscope 402, while twoother cables 407 and 408 connect the invention 401 to the circuit undertest 403.

The set-up of FIG. 4 supports a very wide range of measurementsdepending on the timing and output modes selected. To illustrate oneexample, the regulated-output protocol has been selected, the type-1output is an alternating voltage level that controls an operationalstate on the circuit under test 403, and the type-2 output is a pulsethat activates a response from the circuit under test 403, and thereadiness output is used to trigger the oscilloscope 402. Afterconnecting up the cables and positioning the probes, the user issues adouble-syllable command. Upon the command sound, the readiness outputimmediately goes low, and passes through cable 406, and triggers theoscilloscope 402 on a slow trace. Then the type-2 output pulse, from thesame command, passes through cable 407 and prompts the circuit undertest 403 to produce a diagnostic voltage. The command also resets theregulator parameter. The oscilloscope 402 then measures the diagnosticvoltage waveform. Then, with the measurements still in progress, theuser issues a single-syllable command which causes a type-1 outputsignal, which in the alternating-output mode comprises an output voltagethat changes between +5 volts and zero upon each command. This voltagetravels to the circuit under test 403 using the cable 408, therebymodulating the behavior of the circuit under test 403. Then, the userissues another double-syllable command, which causes the invention 401to generate another type-2 pulse, which travels along the cable 407 tothe circuit under test 403, again triggering the circuit under test 403to initiate a behavior that is to be measured, but this time with theopposite voltage on cable 408. The oscilloscope 402 reveals anydifferences in the behavior of the circuit under test 403 under the twoconditions modulated by the type-1 output signal, thereby accomplishingthe desired measurement. The alternating type-1 signal could also bedisplayed on the oscilloscope 402 simultaneously, by adding anothercable. Many other measurements and options are possible using theinvention 401, depending on the outputs selected for various functions,the output mode and timing selected, and the command sequence employed.

FIG. 5 shows a time chart of the various signals and pulses. This chartapplies to an embodiment that treats all commands as single-syllablecommands, and then generates either a pulse or alternating outputsignal. Any additional syllables are ignored. The immediate timing modeis assumed. The first trace, labeled Sound, shows the amplified soundsignals as a function of time. A noise pulse and two command sounds areshown. The horizontal dashed line shows the threshold. The verticaldotted lines show synchrony.

The second trace, labeled Rectified, shows the amplified signalsfollowing optional rectification and smoothing. This improves the noiserejection in certain environments, but places additional requirements onthe user to emphasize vowel sounds clearly. The inventive method maydetect sounds by comparing either the rectified or unrectified signalsto a threshold.

The third trace in FIG. 5, labeled Detected, shows schematically whenthe amplified signal exceeds the threshold. The noise pulse and the twocommand sounds are detected. Optionally, the rectified signals couldhave been compared to a threshold, with essentially the same result.

The fourth trace, labeled Td-Periods, shows the deadtime intervals whenthe system waits for prior sounds to die down before accepting commands.During the Td period, if any sound is detected before the Td periodexpires, then the Td period is started over, and continues until a fullTd interval passes with no further detected sound. This is illustratedwhen the noise pulse occurs. Since the noise pulse occurs before the Tdperiod is finished, the noise causes Td to retrigger (start over) andthen continue for a full Td period after the end of the noise pulse.

The fifth trace shows the readiness output signal, which indicates whenthe system is ready to receive a voice command. Initially, the system isinhibited due to the deadtime period, and the readiness signal istherefore low. Then, following the noise, plus the Td period, thedeadtime requirement is finally satisfied, and the system becomes readyto receive commands. Thus the readiness signal goes high when Td expireswith no further sound detected. Then, as soon as the first sound ofcommand 5.1 is detected, the readiness signal immediately goes lowagain, thereby indicating that command processing is in progress.Readiness then stays low until the end of the command processing, plusanother Td period. In this way the system prevents double-pulsing, andalso informs the user when the invention can receive voice commands witha visual readiness indicator.

The sixth and seventh traces, labeled Output (pulse) and Output (alt),show the output signals for the pulse output mode and alternating outputmode of operation respectively. No output signal is shown for the noisepulse because the readiness is low at that time, since the initial Tdperiod has not yet completed. Therefore the noise pulse is ignored. Ateach command sound, on the other hand, the deadtime has finished and thereadiness signal is high. Therefore the system recognizes both commandsand produces a type-1 output signal upon each command sound. The outputsignal is a brief output pulse (in pulse mode) or an alternating voltagelevel (in alternating mode) responsive to each command.

FIG. 6 is a flowchart showing the inventive method for single-syllablecommands, with output signals being either a pulse or an alternatingvoltage. First, the invention waits for a time of duration Td withoutdetectable sound. It does this by repeatedly re-starting the Td periodwhenever a sound is detected, as indicated by the interrogator labeled“Sound?”. When the Td period expires with no further sound beingdetected, the readiness indicator is illuminated and the readinessoutput signal is generated, thus showing that the invention is ready toreceive a voice command.

Then, the invention waits until the first sound is detected, which isinterpreted as a command sound. The readiness indicator and readinessoutput are then turned off and the output signal is generated. Dependingon the output mode, the output signal is either a pulse output or analternating voltage level. Then the cycle resumes by again waiting for aTd deadtime period.

The method illustrated in FIG. 6 is suitable for a relatively simpleset-up in which the invention generates just one type of pulse, which isused to trigger a scope or activate a circuit upon voice command.

FIG. 7 shows the sequence of sounds and pulses for a more versatileembodiment recognizing both one-syllable and two-syllable commands, inregulated mode, with pulse outputs. The top trace labeled Sound shows asingle-syllable command labeled 7.1, a double-syllable command labeled7.2, and then another single-syllable command 7.3. The trace labeledDetected shows when the sound exceeds the threshold. Td-Periods showsthe deadtime intervals (in this case, a post-deadtime following eachdetected sound). Ta-Periods shows the short Ta period marking the end ofthe first syllable in each command. If any sound occurs while Ta isbeing measured, then the Ta clock is started over, and continuing untilno further sound is detected, thereby marking the end of the firstcommand syllable.

After the Ta period, a Tg period is marked to detect a second syllable,if any. If a sound occurs in Tg, then the command has two syllables. Ifno sound is detected in Tg, then the command has only one syllable.Accordingly, commands 7.1 and 7.3 have no additional sound in theirrespective Tg periods, and thus register as single-syllable commands,whereas command 7.2 shows the sound of the second syllable beingdetected in Tg. In this way the method determines whether a command is asingle-syllable or double-syllable command.

Following each Tg period is a deadtime interval Td as shown in theTd-Periods trace. The next trace shows the readiness parameter, whichstarts out ready, but becomes not-ready (low) as soon as the firstcommand sound is detected. Readiness stays low while the command isbeing processed, until after the subsequent deadtime, and only thenreturns to the high or ready state. The same pattern is repeated foreach command; readiness goes low upon the first sound of the command andremains low until after the various command processing intervals plus aTd interval.

The next trace shows a type-2 output pulse, responsive to thedouble-syllable command 7.2. The pulse occurs immediately when thesecond sound of the command is detected. In the regulated-output mode,the output signal is generated immediately upon the sound of thesyllable corresponding to the expected command, rather than waitinguntil the end of Tg.

The Regulator trace shows the regulator parameter which regulates theproduction of type-1 signals. Initially, the parameter is low, meaningtype-1 signals are inhibited. Accordingly, the command 7.1 produced nooutputs, despite being correctly detected while readiness was high. Butsince the regulator parameter was still low at that point, thesingle-syllable command 7.1 was ignored.

As soon as the double-syllable command 7.2 is recognized, the regulatorparameter goes high, thereby re-enabling single-syllable commands.Regulator remains high until the next sound, which is thesingle-syllable command 7.3. A type-1 output is then generated becausethe regulator parameter is enabling when command 7.3 is received. Then,the regulator goes low to inhibit any subsequent type-1 outputs. Thisillustrates that in regulated-output mode, type-1 outputs are inhibiteduntil being reset by a double-syllable command.

After the command 7.3, the sequence of Ta-Tg-Td is repeated as usual.Then, readiness goes high since the system is ready to receive anothercommand, but the regulator is still low because the last command was atype-1. In the regulated-output mode, only one type-1 output is allowedafter each double-syllable command, and any further single-syllablecommand responses are inhibited until being reset by anotherdouble-syllable command. Accordingly, if the command 7.3 had in factbeen a type-2, then the regulator would have gone high as soon as asecond-syllable sound was detected in the last Tg period. But since 7.3was only a single-syllable command, the regulator stays low.

The last trace, labeled Stepwise output, shows an alternate outputsignal comprising a first voltage level upon the first syllable of anycommand, followed by a second voltage level if there is a secondsyllable, and so forth. After the Tg period expires, the command isfinished, and the voltage returns to ground. The stepwise output isuseful for triggering multiple instruments or channels by settingdifferent triggering levels for each channel.

FIG. 8 shows a flowchart corresponding to a method that accepts bothsingle- and double-syllable commands, and generates a readiness output,and generates pulse outputs. Both the immediate and regulated outputoptions are included as options. In the regulated-output mode, theregulator parameter is disabled after each type-1 and re-enabled aftereach type-2. In the immediate-output mode, on the other hand, theregulator parameter is always enabled, so the first sound alwaysgenerates the type-1 pulse.

The flowchart of FIG. 8 starts with a Td deadtime, then turns on thereadiness indicator and readiness output, then waits for a command. Uponthe first sound, it immediately turns off the readiness indicator andreadiness output. It also generates a type-1 output if the regulatorparameter is set to enable type-1 outputs. But if the regulatorparameter is still disabling when the command is detected, then thecommand is ignored and no type-1 output is generated.

Continuing with the flowchart, the end of the syllable is then found bywaiting for a Ta interval with no sound. After that, a Tg interval ismarked, and if any sound is detected during Tg, a type-2 output isgenerated and the regulator is set to enabling. However, if Tg expireswith no further sound, then the command was a single-syllable command.When a single-syllable command is recognized, the regulator is set todisabling if the regulated-output mode has been selected. But if theregulated-output mode has not been selected (ie, the immediate-outputmode has been selected), then the regulator parameter remains enabled.The method then goes back to the deadtime step and repeats.

Thus in the regulated-output mode, a single-syllable command produces atype-1 output only if the regulator parameter is enabling, and then setsit to disabling; while a type-2 command resets it back to enabling. Inthe immediate-output mode, the parameter always remains enabling, so thefirst syllable of every command generates a type-1 output.

As a slight alternative, the regulator parameter could be turned off assoon as the type-1 output is generated, as was illustrated in FIG. 7.Operationally, it makes no difference whether parameter is set at thebeginning or end of the Tg period.

A three-syllable command generating a type-3 output would be processedin much the same way, except that the Ta-Tg sequence would be repeatedtwice for each command, thereby detecting all three syllable sounds aswell as the two intervening gaps.

The embodiments and examples provided herein illustrate the principlesof the invention and its practical application, thereby enabling one ofordinary skill in the art to best utilize the invention. Many othervariations and modifications and other uses will become apparent tothose skilled in the art, without departing from the scope of theinvention, which is to be defined by the appended claims.

The invention claimed is:
 1. A device to generate an output signal toactivate a triggerable electronic system responsive to a spoken command,said device comprising: a microphone and an amplifier configured toconvert sound waves of the spoken command into amplified signals; aprocessor configured to generate the output signal when the amplifiedsignals exceed a threshold level; and a connector carrying the outputsignal detachably connected to the electronic system; wherein theprocessor is further configured to generate a type-1 output signalresponsive to a single-sound command having only one voiced period, andto generate a type-2 output signal distinct from the type-1 outputsignal responsive to a double-sound command having two voiced periodsseparated by an interval of substantially less sound; and wherein theprocessor is further configured to set a regulator parameter to anenabling state and a disabling state; and wherein the processor isfurther configured, if the regulator parameter is in the enabling state,to immediately generate the type-1 output signal and set the regulatorparameter to the disabling state, responsive to any command sound; andwherein the processor is further configured, if the regulator parameteris in the disabling state, to generate no output signals and to leavethe regulator parameter in the disabling state, responsive to asingle-sound command; and wherein the processor is further configured togenerate the type-2 output signal and set the regulator parameter to theenabling state, responsive to a double-sound command; thereby activatingthe triggerable electronic system responsive to the spoken command whileensuring that the type-1 output signal is generated immediately upon thefirst sound following a double-sound command, and that any subsequentsingle-sound commands will be ignored until another double-sound commandis detected.
 2. The device of claim 1 wherein the triggerable electronicsystem comprises a measurement instrument that, when activated by theoutput signal, measures one or more diagnostic voltages on a circuitunder test.
 3. The device of claim 1 wherein the triggerable electronicsystem comprises a circuit under test that, when activated by the outputsignal, generates one or more diagnostic voltages that are measured by ameasurement instrument.
 4. The device of claim 1 wherein the outputsignal comprises one of: an electronic pulse of fixed amplitude andduration; a voltage level that alternates between two fixed voltagevalues upon each voice command; a voltage level that depends on how manysyllables comprise the spoken command; a waveform whose amplitude orfrequency depends on how many syllables comprise the spoken command; ora digital communication message.
 5. The device of claim 1 which furtherincludes a readiness output connector, and wherein: the processor isfurther configured to generate a readiness output signal on thereadiness output connector; the readiness output signal comprises afirst voltage level while the device is ready to respond to voicecommands; and the readiness output signal comprises a second voltagelevel distinct from the first voltage level while the device isinhibited from responding to voice commands.
 6. The device of claim 1which further includes at least one visual indicator that indicates anoperational parameter of the device, the indicator being in the list of:an indicator indicating when the device is ready to respond to a voicecommand; an indicator indicating when the device is inhibited fromresponding to voice commands; an indicator indicating when the devicegenerates the output signal; and an indicator indicating when a batteryvoltage is below a predetermined value.
 7. The device of claim 1 whichfurther includes a wearable speaker which is detachably connected to theprocessor, and wherein the processor, cooperating with the speaker,produces an audible sound when the output signal is generated.
 8. Thedevice of claim 1 wherein the processor is further configured togenerate a type-3 output signal, distinct from the type-1 and type-2output signals, responsive to a triple-sound command having three voicedperiods separated by intervals of substantially less sound.
 9. A methodfor activating an electronic system responsive to a spoken command, saidmethod including a regulator parameter that has an enabling state and adisabling state, said method comprising the steps: converting soundwaves to raw electronic signals, and amplifying the raw signals to makeamplified signals; comparing the amplified signals to a predeterminedthreshold value, a spoken command sound being detected when theamplified signals exceed the threshold value; then, waiting until afirst command sound is detected; then, waiting until a period Ta expireswith no further sound detected therein, thereby determining that thefirst sound period of the command has finished; then, waiting for asecond command sound during a period Tg; then, if no further sound isdetected during Tg, determining that the command is a single-soundcommand, and if any sound is detected during Tg, determining that thecommand is a double-sound command; then, responsive to a single-soundcommand, generating an electronic output signal comprising a type-1output signal if the regulator parameter is in the enabling state, andinhibiting all type-1 output signals if the regulator parameter is inthe disabling state; and responsive to a double-sound command,generating a type-2 output signal distinct from the type-1 signal, andsetting the regulator parameter to the disabling state; and then,conveying the output signal to the electronic system, thereby activatingthe electronic system.
 10. The method of claim 9 which further includesgenerating a readiness signal that indicates whether voice commands canbe received, including the steps: setting the readiness signal toindicate that voice commands can not be received; then, while rejectingall voice commands, waiting until a deadtime period Td expires with nofurther sound detected therein; then, setting the readiness signal toindicate that voice commands can be received; then, waiting until asound is detected exceeding the threshold value; then, generating theoutput signal.
 11. The method of claim 9 which further includes adelayed-output mode wherein the type-1 or type-2 output signal isgenerated only after the period Tg is finished.
 12. The method of claim9 which further includes an immediate-output mode wherein the type-1output signal is generated immediately when the first sound of a commandis detected, and the type-2 output signal is generated immediately whenany sound is detected during the Tg period.